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/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef TREECODER_H
#define TREECODER_H
#define vp8_prob_half ((vp8_prob) 128)
typedef unsigned char vp8bc_index_t; /* probability index */
typedef unsigned char vp8_prob;
typedef signed char vp8_tree_index;
struct bool_coder_spec;
typedef struct bool_coder_spec bool_coder_spec;
typedef struct bool_writer bool_writer;
typedef struct bool_reader bool_reader;
typedef const bool_coder_spec c_bool_coder_spec;
typedef const bool_writer c_bool_writer;
typedef const bool_reader c_bool_reader;
/* We build coding trees compactly in arrays.
Each node of the tree is a pair of vp8_tree_indices.
Array index often references a corresponding probability table.
Index <= 0 means done encoding/decoding and value = -Index,
Index > 0 means need another bit, specification at index.
Nonnegative indices are always even; processing begins at node 0. */
typedef const vp8_tree_index vp8_tree[], *vp8_tree_p;
typedef const struct vp8_token_struct
{
int value;
int Len;
} vp8_token;
/* Construct encoding array from tree. */
void vp8_tokens_from_tree(struct vp8_token_struct *, vp8_tree);
void vp8_tokens_from_tree_offset(struct vp8_token_struct *, vp8_tree, int offset);
/**
* Convert array of token occurrence counts into a table of probabilities
* for the associated binary encoding tree. Also writes count of branches
* taken for each node on the tree; this facilitiates decisions as to
* probability updates.
*/
void vp8_tree_probs_from_distribution(int n, /* n = size of alphabet */
vp8_token tok[/* n */],
vp8_tree tree,
vp8_prob probs[/* n-1 */],
unsigned int branch_ct[/* n-1 */][2],
const unsigned int num_events[/* n */],
unsigned int Pfactor,
int Round);
#endif /* TREECODER_H */
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